Biodegradable surface active agents having good foam properties and foam stabilizing characteristics

ABSTRACT

HETERIC POLYETHER POLYOLS ARE PREPARED BY THE COPOLYMERIZATION OF LOW MOLECULAR WEIGHT ALKYLENE OXIDES AND A-OLEFIN OXIDES CONTAINING FROM TEN TO TWENTY CARBON ATOMS WITH LOW MOLECULAR WEIGHT ACTIVE HYDROGEN-CONTAINING COMPOUNDS.

Int. Cl. C07c 43/04 US. Cl. 260-615 B 6 Claims ABSTRACT OF THEDISCLOSURE Heteric polyether polyols are prepared by thecopolymerization of low molecular weight alkylene oxides and u-olefinoxides containing from ten to twenty carbon atoms with low molecularweight active hydrogen-containing compounds.

The present application is a continuation-in-part of copending U.S.Patent Application Ser. No. 148,976 filed June 1, 1971 now abandoned,which is in turn a continuation-in-part of US. Patent Application Ser.No. 845,516 filed July 28, 1969, now abandoned.

This invention relates to heteric polyether polyols and methods fortheir preparation. It is more particularly concerned with hctericpolyether polyols which are biodegradable surface active agents havinggood foam properties and foam stabilizing characteristics.

Polyether polyols obtained from the reaction of alkylene oxides withactive hydrogen-containing compounds are well known. These polyetherpolyols have found wide use throughout industry and in the home inapplications where it is desirable to reduce the surface tension of aliquid so that it will become more miscible with other liquids or willeasily wet the surfaces of solid materials. These compounds may be foundin the form of solids or liquids; they may be both foamers anddefoamers; they may range from hydrophobic to hydrophilic; and they mayvary considerably in their resistance to degradation of bacterialattack. With respect to the present invention, three properties are ofparticular importance, namely, (1) the product must have a high degreeof biodegradability, (2) the product must have good foam properties, and(3) the product must have good foam stabilizing characteristics.

It is an object of this invention to provide a novel, nonionic surfaceactive agent. It is another object of this invention to provide anonionic composition which is biodegradable, has good foam stability andfoam stabilizing characteristics. It is still another object of thisinvention to provide a process for preparing hydrophilic polyetherpolyols. Still other objects will appear from the more detaileddescription of this invention which follows.

According to this invention, polyether polyols having a molecular weightof from 400 to 6000, preferably from 1000 to 4000, are prepared byreacting a mixture of ethylene oxide and an a-olefin oxide with a lowmolecular weight active hydrogen-containing compound. It is to beunderstood that the ethylene oxide can be used in ad- 3,829,506 PatentedAug. 13, 1974 mixture with other low molecular weight alkylene oxidesand that a mixture of u-olefin oxides can be employed. The amount of lowmolecular weight alkylene oxide used in the reaction will vary so thatthe resulting product will have varying degrees of hydrophilicity,depending upon the desired application of the polyether polyol. -In anycase, this requires an ethylene oxide addition in an amount such thatthe resulting polyol contains from about 40 to 80% by weight ethyleneoxide, and preferably from about 40 to 60% ethylene oxide. The amount ofa-olefin oxide required will be an amount sufficient to react with atleast one active hydrogen of the active hydrogen-containing compound.The copolymerization is carried out in the presence of a basic catalystat an elevated inert gas pressure in a suitably heated reactor. Thereaction may be carried out in the presence or in the absence of aninert organic solvent.

It has been found that in the preparation of the polyether polyols ofthe present invention, it is necessary to copolymerize the ethyleneoxide and a-olefin oxide with the active hydrogen-containing compounds.Thus, when the a-olefin oxide is mixed with the active hydrogen compoundat reaction conditions, the two components separate and very little, ifany, reaction occurs. However, as soon as the low molecular weightalkylene oxide is added, the reaction immediately proceeds. The reasonfor this is not known, but it is believed that the alkylene oxide actsas a solubilizing agent, dissolving the a-olefin oxide and activehydrogen-containing compound, thus increasing the reactive sites of thereactants.

The above-described polyether polyols, when formulated with othercompounds, have many applications. Since the polyols have excellent foamstability and biodegradable properties, the polyols are useful in manytypes of detergents. These include light-duty detergents, such as handdishwashing and fine fabric washing, heavy-duty detergents, all-purposeliquid cleaners, rinse aids, sanitizers, bubble baths, shampoos, andmetal cleaners, just to name a few. The polyether polyols of thisinvention can also be used as saturants for film faced dressings of thetype having relatively low adherence to healing wounds, as carriers fora spermicidal vaginal pharmaceutical concentrate for producing foam withaerosol propellants, and as agents to increase foam height and foamstability of other nonionic surfactants. It has also been found thatthese polyols undergo the typical reactions of alcohols. Formation ofinorganic and organic esters are possible by reaction of the polyolswith sulfuric acid, phosphoric acid, and monoor polycarboxylic acids.Other ethers may be prepared by reaction of these polyols with benzylchloride, alkyl chloride, and the like. The terminal hydroxyl groups maybe replaced by chlorine if reacted with thionyl chloride. Urethanes mayalso be prepared by reacting these polyols with isocyanate-containingcompounds.

The low molecular weight active hydrogen-containing compounds that maybe used in the practice of this invention are the polyhydric alcoholshaving from about two to ten carbon atoms and from about two to sixhydroxyl groups. These include, for example, alkane polyols, such asethylene glycol, propylene glycol, 1,4-butane diol, l,2 butane diol,trimethylolpropane, glycerol, 2,3,5,6-heXane tetrol, sorbitol,pentaerythritol, glucose and the like; alkene polyols, such as2-butene-l,4-diol, 2-hexene-l,4,6- triol, 3-heptene-1,2,6,7-tetrol,1,5-hexadiene-3,4-diol, and

and the like; the alkylene polyols, such as 2-butyne-1,4- diol,2-hexyne-1,4,6-triol, 4-octyne-1,2,7,8-tetrol, and the like; andoxyalkylene polyols, such as diethylene glycol, triethylene glycol,tetraethylene glycol, dipropylene glycol, tripropylene glycol, and thelike.

The a-olefin oxides which may be used in this invention are those oxidescontaining from about ten to twenty carbon atoms. The amount of a-olefinoxide required to react with a polyhydric alcohol will be at least onemole of a-olefin oxide per mole of polyhydric alcohol. The ratio of fromabout 1.0 mole to about 1.5 moles of aolefin oxide per mole ofpolyhydric alcohol when the alcohol is a triol is the preferred ratioand for tetrafunc tional and higher polyfunctional alcohols, a moleratio of 2 to 3 moles of a-olefin oxide per mole of polyhydric alcoholis preferred. Examples of the a-olefin oxides which may be used in thepractice of this invention include, decylene oxide, undecylene oxide,dodecylene oxide, tridecylene oxide, tetradecylene oxide, pentadecyleneoxide, hexadecylene oxide, heptadecylene oxide, octadecylene oxide,nonadecylene oxide, eicosylene oxide and mixtures thereof. Mixtures ofa-olefin oxides are commercially available under the trademark Nedox1114 and Nedox 1518. Nedox 1114 is a mixture of a-Olefin oxides havingan average molecular weight of 189 containing approximately 25% byweight of a C olefin oxide, 25% by weight of a C olefin oxide, 25 byWeight of a C olefin oxide and 25% by weight of a C olefin oxide. Nedox1518 is a mixture of a-olefin oxides having an average molecular Weightof 245 containing approximately 29% by weight of a C olefin oxide, 29%by weight of a C olefin oxide and 29% by weight of a C olefin oxide and13% by weight of a C olefin oxide.

The low molecular weight alkylene oxides that may be used in thepractice of this invention are alkylene oxides containing from two tofour carbon atoms. These include ethylene oxide, 1,2-propylene oxide,1,2-butylene oxide, 1,3-butylene oxide, 1,4-butylene oxide and 2,3-butylene oxide. Ethylene oxide or a mixture of ethylene oxide with oneor more other alkylene oxides is preferred. If a mixture of ethyleneoxide and another lower alkylene oxide is employed in the invention, themixture should contain at least fifty weight percent ethylene oxide. Theamount of low molecular weight alkylene oxide required in the practiceof this invention is an amount suflicient to impart the desired foamingand foam stabilizing characteristics of the polyol. Amounts greater thanthis unbalance the desired hydrophilic-hydrophobic characteristics ofthe resulting polyol. It has been found that at least three moles ofethylene oxide per mole of polyhydric alcohol are required to produce apolyol with hydrophilic characteristics.

Any suitable prior art alkaline oxyalkylation catalyst can be used inthe practice of this invention. These include, for example, strongbases, such as sodium hydroxide, sodium methylate, potassium hydroxide,and the like; salts of strong bases with weak acids, such as sodiumacetate, sodium glycolate, and the like and quaternary ammoniumcompounds, such as benzyl dimethyl cetyl ammonium hydroxide, and thelike. The concentration of these catalysts in the reaction mixture isnot critical and may vary from about 0.1% to 5% by weight of thepolyhydric alcohol reactant.

An inert organic solvent may be utilized in the abovedescribedprocedures. The amount of solvent used is that which is sufficient toprovide a suitable reaction medium and is generally on a molar basis inexcess of the total amount of the reactants. Examples of suitablesolvents include aliphatic hydrocarbons, such as hexane, heptane,isoheptane; aromatic hydrocarbons, such as benzene, toluene, xylene;chlorinated hydrocarbons, such as carbon tetrachloride, ethylenedichloride, propylene dichloride; and oxygenated hydrocarbons, such asdiethyl ether, dimethyl ether, anisole, and the like.

In accordance with this invention, a polyether polyol is prepared bymixing a low molecular weight polyhydric alcohol containing from two toten carbon atoms and from two to six hydroxyl groups with from about 1.0mole to 3.0 moles per mole of alcohol of an a-olefin oxide having fromten to twenty carbon atoms; heating said mixture to a temperature in therange of about 50 C. to 150 C., preferably from C. to 130 C. under aninert gas pressure preferably from about 34 p.s.i.g. to p.s.i.g.; addingethylene oxide or a mixture of ethylene oxide and other alkylene oxideshaving from three to four carbon atoms to said mixture in an amount sothat the resulting polyether polyol product will contain from 40% to 80%by weight ethylene oxide; and maintaining said mixture at a temperatureand pressure in said range for a period of about one hour to ten hours,preferably one to three hours. If desired a catalyst may be added to thereaction mixture prior to the ethylene oxide addition. Alkalinecatalysts such as potassium hydroxide or acid catalysts such as borontrifluoride are useful as is well established in the art. Generally, theamount of ethylene oxide utilized, whether singly or in admixture withother low molecular weight alkylene oxides, will be from about 3 to 30moles per mole of polyhydric alcohol.

The following examples will illustrate the practice of this invention,but are not to be considered as being unduly limitative thereof. The OHnumber in the examples was deterbined by ASTMD1638-61T and the surfacetension measurements were determined With a Du Nuoyes Tensiometer. Thewetting time was determined by the Draves cotton skin test AATCC testmethod 17-1952 evaluation of wetting agents, using a 3-gram hook.

To evaluate the foam characteristics of a composition of the presentinvention, a solution was prepared by dissolving a given amount of saidcomposition or mixtures of said composition in tap water and placing 10liters of said solution in a Pyrex jar measuring 10" in diameter and 10"in height. This Pyrex jar was equipped with a propeller-type stirrer,knife blade heaters, a thermoregulator and a thermometer. A smallcentrifugal pump was arranged to circulate the solution contained inthis jar through a calibrated glass flow meter toa jet orifice preparedfrom the base of a No. 20 Becton-Dickerson & Company hypodermic needleby enlarging the hole in the base with a No. 56 twist drill. The jetorifice Was mounted coaxiaIly inside a Pyrex glass tube (51 mm. by 910mm.) which was placed vertically in the solution. The jet was positionedso that it was 700 mm. above the surface of the solution in the jar, andthe Pyrex tube was arranged to project 210 mm. below the surface of thesolution.

The solution was brought to F. by means of the knife blade heater andmaintained at a constant temperature by means of the therrnoregulator.The centrifugal pump was started and the flow rate of solution wasmetered through the jet. The flow was adjusted to 400 ml./ min. byby-passing part of the stream back into the Pyrex jar before passagethrough the flow-meter. The solution passing through the jet wasdirected against the wall of the vertical tube while the flow wasadjusted and the temperature was equilibrated to prevent foaming priorto the actual determination. The jet was then arranged to pass thesolution coaxially downward through the center of the tube to impingeupon the surface of the solution located in the Pyrex tube. Timing wasinitiated from the instant the solution impinged on the liquid surfaceand continued until the foam reached 600 mm. or until the foaming timeof ten minutes had transpired. At this point, timing was re-initiated todetermine the relative foam stability after five minutes. The foamheight readings were obtained from a calibration on the outside of thePyrex tube with a zero mark being at the surface of the solution.

By the term heteric as used in this specification is meant that thepolyols possess random distribution of oxyalkylene groups.

EXAMPLES I-IV The following examples illustrate the preparation ofpolyether polyols of the present invention by copolymerization of aa-olefin oxide and ethylene oxide with glycerol.

temperature. The mixture was then cooled to 50 C. and discharged.

The resulting polyether polyol was found to have an OH number of 266, acloud point of 55 C. at a concentration of 1% by weight polyol in water,and a sur- 5 Into a one-gallon autoclave, 184 grams of glycerol, 430face? tension of (.iynes per cfmtlmeter at .concen tration of 0.1% byweight polyol 1n water. Foaming tests grams of a mixture of C to Ca-olefin oxides having illustrated that the polyol foamed to 600millimeters 1n a molecular Welght of and 3 grams of Sodlum hyfiveminutes and deea ed to 450 millimeters in five droxide were charged. Areduced pressure of mm. of minutes y mercury was then applied whileheating the mixture to 10 EXAMPLES VLVIH 80 C. The temperature wasmaintained at 80 C. for five minutes, after which the autoclave waspressurized The following examples illustrate the foam stabilizing undernitrogen to 34 p.s.i.g. The temperature was then and foam enhancingproperties of polyether polyols of increased to about 130 C. and varyingamounts of ethylthe present invention when combined with other nonionicene oxide were added. The addition of ethylene oxide to 15 surfaceactive agents. Three tests, identifiable as Tests the mixture was doneat 130 C. for a period of two 1, 2 and 3, were made for each example inorder to illushours. The mixture was held for another 45 minutes attrate these foaming properties. Test 1 was made with a this temperature.The mixture was then cooled to 50 C. solution containing 0.1% by weightof a nonionic. Test and discharged. 2 was made with a solutioncontaining 0.002% by weight Tables 1 and 2, below, illustrate the molarratios of of a polyether polyol of the present invention. Test 3ethylene oxide to glycerol and the physical properties of was made witha solution containing 0.1% by weight of the resulting polyol of eachexample. The mixture of a nonionic and 0.002% by weight of a polyetherpolyol a-olefin oxides employed in the following examples comof thepresent invention. prised a proximately equal weight prop rt s of ir Toevaluate the foam characteristics of these examples, C C and -olefinoxides. the prescribed amount of nonionic, polyether polyol or TABLE 1Foam properties Descent reading, Moles oi- Ascent time mm. at

a-Olefin Ethylene OH Min- Sec- Finish Example Glycerol oxide oxide No.utes onds Start (5 min.)

TABLE 2 mixture of the nonionic and polyether polyol was prepared in tapwater and run according to the procedure described Properties of 0.1% byprevious1y 11 1 h 1 pojnt f welg 33 55,? F01 The following polyetherpolyol IlOHiOl'llCS were used 1 e v for these tests. Nonionics definedas Polyether Polyol A weight Surface pol ivetlher u isioni wetting and}?Were corgpositiorllg of the present invention where- P Y m Y as onionicsan were com ositions reviousl d P y Example water cm Sewn 5 known in theart. Table 3, below, illustrates the results.

58 49 3 5: 31.5 65 Polyether Polyol A 34 30.3 74

Biodegradability was determined for Examples II and III according to theprocedure outlined in the article Foam Generation Method for EvaluatingBiodegradability by L. R. Bacon in The Journal of the American OilChemists Society, January 1966, pages 18-25. These Examples were foundto have better than 95% biodegradation within five days.

EXAMPLE V The following example illustrates the preparation of apolyether polyol of the present invention by copolymerization of anu-olefin oxide and ethylene oxide with glycerol.

Into a one-gallon autoclave, 184 grams of glycerol, 531 grams of amixture of C to C a-olefin oxides having a molecular weight of 245, saidmixture described in the specification and identified as Nedox 1518, and3 grams of sodium hydroxide were charged. A reduced pres sure of 10 mm.of mercury was then applied while heating the mixture to 80 C. Themixture was maintained at 80 C. for five minutes, then the autoclave Waspressurized under nitrogen to 34 p.s.i.g. The temperature was thenincreased to about 130 C. and 58.6 grams of ethylene oxide was addedover a period of two hours at 130 C. The mixture was held for another 45minutes at this This was a nonionic surfactant of the present inventionprepared from the reaction of one mole of glycerol, one mole of amixture of a-olefin oxides having from fifteen to eighteen carbon atoms,and 6.65 moles of ethylene oxide, more fully described hereinbefore andidentified as Nedox 1518.

Polyether Polyol B This was a nonionic surfactant prepared by thesequential condensation of propylene and ethylene oxides with propyleneglycol. It had two terminal hydroxyl groups, a molecular weight of about2,000 and an oxyethylene content of about 40% by weight.

Nonionic D This was a nonionic amine-based tetrol surfactant prepared bythe sequential addition of propylene and ethylene oxides to ethylenediamine. It had a molecular weight of about 1,250 and an oxyethylenecontent of about 40% by weight.

After the addition was completed, the reaction mixture was maintained at135 C. for an additional hour. The

TABLE 3 Ascent Descent Time Time Min- Sec- Example Test Surfactants utesonds Mm. Minutes Mm 1 Nonionic C 10 150 5 30 VI 2 Polyether polyol B 1O35 5 25 3 Plus 13 4 57 600 5 560 l Nonlonic C. 150 5 VIII 2 Polyetherpolyo 10 32 5 25 3 C plus A" 3 47 600 5 550 1 Nonionic D". 10 510 5 0VIII 2 Polyether polyol A" 10 32 5 25 3 "D" plusA 2 27 600 5 500 As canbe seen from Table 3, the addition of a polyether polyol of the presentinvention to other nonionic surface active agents enhances the foamheight and increases the foam stability of said nonionics.

EXAMPLE IX The following example illustrates the preparation of apolyether polyol of the present invention by copolymerization of anot-olefin oxide and ethylene oxide with trimethyloylpropane.

Into a one-gallon autoclave, 134 grams of trimethylolpropane, 430 gramsof a mixture of C to C a-Ol6fiI1 oxides, and 4 grams of sodium hydroxidewere charged. A reduced pressure of 10 mm. of mercury was then appliedwhile heating the mixture to 80 C. The mixture was maintained at 80 C.for ten minutes, then the autoclave was pressurized under nitrogen to 34p.s.i.g. The temperature was then increased to about 130 C. and theaddition of ethylene oxide was started. 805 grams of ethylene oxide wasadded over a period of two hours and 35 minutes at 130 C. The mixturewas held for another one hour and thirty minutes at this temperature.The mixture was then cooled to 50 C. and discharged.

The resulting polyether polyol was found to have an OH number of 131, acloud point of 75 C. at a concentration of 1% by weight polyol in water,and a surface tension of 28.7 dynes per centimeter at a concentration of0.1% by weight polyol in water. Foaming tests illustrated that thepolyol foamed to 600 millimeters in five minutes and decayed to 430millimeters in five minutes.

EXAMPLE X The procedure of Example IX was duplicated with the exceptionthat 420 grams of 1,2-epoxydodecane (dodecylene oxide) was substitutedfor the mixture of oxides employed in Example IX. The resulting polyolhas a hydroxyl number of 135 and a cloud point of 75 C. at aconcentration of 1% by weight polyol in water. Foaming tests indicatethat the polyol foamed to 600 millimeters in five minutes and decayed to420 millimeters in five minutes.

EXAMPLE XI Comparative Example (A) Polyol prepared in accordance withthe subject invention: Into a cleaned, dried autoclave, 248 parts ofethylene glycol and four parts of potassium hydroxide were charged. Areduced pressure of less than 10 mm. of mercury was then applied to theautoclave while heating the charge to 80 C. The temperature wasmaintained at 80 C. for ten minutes after which the autoclave waspressurized under nitrogen to 15 p.s.i.g. The temperature of the chargewas then increased to 135 C. at which time a mixture of 1416 parts ofethylene oxide and 860 parts of a mixture of C to C oxides (averagemolecular weight of 215) was added to the charge maintained at apressure of 75-90 p.s.i.g. over a period of ten hours.

reaction mixture was then cooled to 50 C. and discharged. The reactionmixture was filtered with Celite and stiripped of volatiles for one hourat C. under less than one mm. of mercury.

The resulting homogeneous polyol was found to have a hydroxyl number of193.5 and a cloud point (1%) of 53 C. Dynamic Foam Height evaluation(120 F., 400 ml./ min.) illustrated that the polyol foamed to 600millimeters in 2.36 minutes and decayed to 590 millimeters in fiveminutes, indicating a very stable foam.

(B) Polyol of US. Pat. No. 3,240,819: Into an autoclave, 832 parts ofpolyethylene glycol having an average molecular weight of 400 and fourparts of potassium hydroxide were charged. The vessel was pressurizedand heated as described above. To the reaction vessel was added 430parts of a mixture of C to C oxides (average molecular weight of 215).The temperature of the charge was maintained at C. After a four-hourperiod, the reaction mixture was cooled to 50 C. and. discharged. Thereaction mixture was filtered with Celite and stripped of volatiles forone hour at 125 C. under less than one mm. of mercury.

The resulting polyol was found to separate on standing, i.e.,non-homogeneous, to have a hydroxyl number of 195 and a cloud point (1%)of 59 C. Dynamic Foam Height evaluation (120 F., 400 ml./ min.)illustrated that the polyol foamed to 90 millimeters in ten minutes anddecayed to 15 millimeters in five minutes.

This example illustrates that a polyol of the subject invention clearlyexhibited better foaming properties than a polyol of the closest priorart.

What is claimed is:

1. A heteric polyether polyol having a molecular weight of from 400 to6,000 prepared by copolymerizing in the presence of an alkalineoxyalkylation catalyst at a temperature between 50 C. and C. for aperiod of from one hour to ten hours under an inert gas pressure, amixture of (a) a low molecular weight alkylene oxide selected from thegroup consisting of ethylene oxide and a mixture of ethylene oxide and alow molecular weight alkylene oxide containing from. three to fourcarbon atoms, said mixture comprising at least fifty weight percent ofethylene oxide,

(b) an a-olefin oxide containing from ten to twenty carbon atoms or amixture of said oxides, and

(c) a polyhydric alcohol having from two to ten carbon atoms and fromtwo to six hydroxyl groups selected from the group consisting of alkanepolyols, alkene polyols, alkyne polyols and oxyalkylene polyols, in amole ratio of (b) to (c) of from about 1:1 to 3:1, the amount of (a)employed being such to provide a polyol containing from 40% to 80% byweight ethylene oxide.

2. The polyol of claim 1. wherein (c) is an alkane polyol.

9 10 3. The polyol of claim 2 wherein (c) is glycerol. 3,031,510 4/1962Crecelius 260-615 B 4. The polyol of claim 1 wherein (a) is ethyleneoxide. 3,607,778 9/ 1971 Lincoln 252-353 5. The polyol of claim 1wherein (a) is ethylene oxide, (b) is a mixture of a-olefin oxides, and(c) is an alkane FOREIGN PATENTS P 5 558,786 6/1958 Canada 260615 B 6.The polyol of claim 5 wherein (c) is glycerol.

References Cited UNITED STATES PATENTS US. Cl. X. R.

3,240,819 3/1966- Gaertne ret a1 260--615 B 10 25289, 106, 307, 321;260Dig. 1, 77.5 AP, 484 B, 3,637,869 1/1972 Seizinger 2606l5 B 484 R,611 A, 953; 424-341 HOWARD T. MARS, Primary Examiner

